Block O ring Problems Help !!

My block at the machine shop has been o-ringed. My machinist talked me into copper head gaskets so I bought a set of Flatout RCC gaskets with .040 compressed thickness, (thinking zero deck). Anyways engine is being assembled and it turns out that my pistons are .016 in the hole, which works out to a .056 quench, not acceptable.

Here are the options we've come up with:

1. Flatout has a .021 thick RCC gasket putting me at .036 quench, I'm comfortable with that number, good parts in the bottom end installed correctly. Only problem Flatout recommends going with no less than their .030 gasket because of the danger of the wire cutting through the gasket. I've done research and apparently most O-rings grooves are cut .029 deep to accept a .041 wire, leaving about .012 wire "above" the deck. In other words more than half the thickness of a .021 gasket. So either go with the .030 gasket giving me a .046 quench, (less than ideal but better), or ignoring Flatout's recommendations and going with the .021 gasket giving me an ideal .036.

2. I'd also consider removing the o-ring wire and going with a composition gasket. Problem is finding a gasket with a round bore and a fire ring that would sit "inside" the o-ring groove. Cometic, (I already called them), tells me that their gaskets are D-shaped for valve clearance, so they probably won't work. If anyone knows of a good quality gasket manufacturer that uses round bores - probably need a 4.050 bore to stay inside the o-ring groove, (my bore is 4.035), I'd love to hear about em.

3. Deck the block and get rid of the groove entirely. Problem here is that if the groove is indeed .029 deep that would put my pistons .013 out of the hole, not going to work. Buying new pistons isn't really an option, I've got about $800.00 in these.

BTW I really don't prefer to run copper gaskets, but It's kind of what I'm stuck with.

Anyways I'd love to hear anyone with experience in this area speak up.

Thanks,

Mark.

Your machinist should have had this all figured out before he started work....measure twice cut once;) That is unless you picked the parts seperate from him...

How much power are you trying to make?
Blower? Nos? Turbo?
SCR? DCR? at current measurements of gasket thickness (.040")
How much has the block already been decked?

It isn't the machinist fault. The block had already been decked an o-ringed when I bought it. I should have researched o-ringed blocks before I bought the thing. Block was fresh when I bought it. It already has splayed caps etc. About the only operations needed on it were a wet tank and honing. I could deck the block down to zero but I'd still be stuck with the ring groove, about .010 deep left if I went completely to zero deck, and left with the same problem. I'm really thinking my best bet may be to just remove the wire, deck the block to my desired height and find a gasket with a fire ring diameter that is "inside" the diameter of the ring groove. I'm going to get the exact ID of the ring groove from my machinist and then see if I can find a gasket that will work.

If I can't do that I'll just look for another block and start over, expensive lesson but this is going to be right.

how about decking the block, then go back and deepen the o-ring channel?

Thought about that too, apparently deepening an existing channel is pretty difficult to do. From what he told me staying in the existing channel without widening it is just about impossible.

Number 2.

My old block was cut for o-rings. Using copper head gaskets even with hylomar, I couldn't seal the water passages. They leaked externally. I installed good Felpro head gaskets and never had a problem since. Just make sure the composite head gasket has a cylinder opening big enough to go around the cylinder and small enough to cover the o-ring groove. I was lucky that my BBC has a good selection of gaskets to use without having odd shapes for valve clearances.

That was gong to be my suggestion, but then again you have to hope that the previous work was done correctly, ie concentric to the cylinder bore. I have CNC mills that can do it no problem, but you might have a hard time finding an automotive machine shop around there that has CNC stuff...might be cost prohibitive too.

I don't really want to mention this, but a long time ago I did a cobb job repair on a friends block that had a couple o-ring grooves cut wrong...I filled them in with JB weld, then re-cut them and it has held up for years....

Number 2.

My old block was cut for o-rings. Using copper head gaskets even with hylomar, I couldn't seal the water passages. They leaked externally. I installed good Felpro head gaskets and never had a problem since. Just make sure the composite head gasket has a cylinder opening big enough to go around the cylinder and small enough to cover the o-ring groove. I was lucky that my BBC has a good selection of gaskets to use without having odd shapes for valve clearances.

Just to make sure I understand correctly I'm looking for a gasket with a fire ring of a small enough diameter so that it fits "inside" the o-ring groove correct. Victor Reinz has a gasket with a 4.100 diameter that may work.